Blast-furnace lining



UNITED STATES PATENT OFFICE.

JAMES GAYLEY, OF BRADDOOK, PENNSYLVANIA.

BLAST-FURNACE LINING.

SPECIFICATION forming part of Letters Patent No. 463,146, dated November 17, 1891.

Application filed July 28,1890- Serial No. 360,227. (No specimens.)

To all whom it mayconccrm Be itknown that I, JAMES GAYLEY, of Braddock, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Blast-F urnace Linings, of which the following is a full, clear, and exact description.

In constructing a blast-furnace the inclosing walls have heretofore been made of a refractory quality of fire-brick. In the lower portion, commonly known as the hearth and bosh, it is of great importance that the brick-work should be maintained as nearly as possible to its original thickness, for as the wear increases there is increased irregularity in the conduct of the process which entails greater expense; but in this portion the wear is very rapid by reason of the chemical action of the molten cinder, which, under the intense heat, has a corrosive and destructive action on the brick-work. The wear at the bosh I have found to be especially injurious to the action of the furnace. As the brick-work becomes corroded there is substituted, however, through the nature of the reactions of the blast-furnace process, a more refractory material, composed largely of carbon, which to some extent arrests this destructive action. It is to this carbon coating that the endurance of the hearth and bosh walls is due. repaired walls that were originally thirty-six inches thick where but six inches of the original brick-work remained, which were protected by such carbon coating of a thickness of eighteen inches. \Vhen the furnacelining is new and before the carbon coating can have had time to form, the deterioration of the walls at the bosh and hearth is very rapid, and during the work of the furnace the character of the charge is apt to vary at times and to produce a corrosive cinder of such chemical nature as will eat away the natural carbon coating and will attack the brick walls. It has occurred to me that the furnace-walls would be much better preserved if the natural process of carbon deposit could be assisted and supplemented by constructing the walls of the hearth and bosh (and preferably also the bottom of the hearth) of a strong and durable material containing carbon in suitable form. The difficulty of accomplishing this is to secure graphitic material sufficiently strong I have to resist the weight of the furnace-walls and the scoring action of the stockas it descends in the furnace. These difficulties I have overcome by. my invention,which consists in constructing the walls of the bosh and hearth of brick compounded of refractory fire-clay and graphitic carbon, such as the substances known in commerce as plumbago, black lead, and graphite. The fire-clay forms a bond for the carbon, giving the bricks the necessary strength and durability to resist compression and abrasion, while making it in the form of bricks or blocks enables it to be built in a strong and substantial manner in the furnace-walls.

To make the bricks I prefer to proceed as follows: In an ordinary pug-mill or dry-pan I mix fire-clay and the graphitic carbon above mentioned in proportions which may be from twenty-five to liftyper centum of graphiticcarbon and from fifty to seventy-five per centum of fire-clay. The most desirable proportions I have found to be about twenty-five per centum of graphitic carbon and seventy-five per centum of fire-clay,though my invention is not limited to any special proportions of the parts, which may be varied according to the judgment of the skilled furnace engineer. This compound I temper and mold into the form of bricks suitable for building in furnace-walls and burn them in the usual manner in the manufacture of fire-brick, and in this operation it will be found that no sensible deterioration is caused by combustion of the carbon; I then build these bricks in the inwalls of the hearth and bosh of the furnace and in the bottom of the hearth, for example,

so that they shall constitute eighteen inches, more or less, of the thickness of the walls, and in setting them I may use as a mortar a mixture of fire-clay and carbon compounded substantially in the manner and in proportions as above stated. The strength of the bricks is such that they do not weaken the structure of the furnace, and in their practical use I have found them of great benefit in preserving the walls, and consequentlyin making the work of the furnace uniform and economical. hen the furnace is first started into blast, instead of presenting bare hearth and bosh walls liable to be corroded by the cinder, the carbon bricks resist this action of the cinder and are themselves renewed and supplemented by the natural deposit of carbon in the furnace. The saving which I thus secure is very considerable and will be appreciated by those Whopract-ice my invention.

In making brick for the boshes I may substitute for the graphitic carbon other forms of -carbon such as pulverized anthracite coal,

charcoal, or coke-though bricks thus made are not so strong or durable.

As an additional improvement I may add to the compoundof Which the bricks are made some lime or other basic material, such as magnesia, which may amount to about twenty I claim-=- 1. A blast-furnace having in the iii-walls of its bosh bricks containing refractory clay and carbon, substantially as and for the purposes described.

2.- A blast-furnace having in the iii-walls of its bosh and hearth bricks containing refractory clay and graphitic carbon, substantially as-and for the purposes described.

3. A blast-furnace having in the in-Walls of its bosh and hearth bricks containing refractory clay and carbon set in mortar of similar composition, substantially as and for the purposesdescribed."

In testimony whereof I have hereunto set' my hand this 24th day of July,.A D. 1890. JAMES GAYLEY. Witnesses:

W. B. (JORWIN,

THOMAS W. BAKEWELL. 

